Fastening device



June 2o, 1939. -W 'A SEWON 2,163,134-

buxsTENIlvG4 DEVICE Filed March zo, 1937 Patented June 20,'- 1939 UNITED 'STAT-Es PATENT OFFICE FASTENING DEVICE Walter A. Semion, Milford, Conn.

Application March 20, 1937, Serial No. 132,017 I 1o claims. (ci. 151414) This invention relates to fastening devices, and

more particularly, to fastening devices which iny clude an externally threaded draft member, as a screw, and a member having a cooperating internal thread, as a nut.

In building up sheet structures by screw and nut securement of the different sheet elements to be joined, a dilculty has been to provide a fastening device which, especially when used for assembling structures of thin sheet metal plates such, for instance, as are employed in airplane manufacture, may be absolutely relied on to insure against accidental disengagement of the screw thread from the nut thread. Not only in airplane manufacture, but in other assemblies of sheet elements, particularlywhen these elements are fairly thin, whether they be of metal or some other material, a fastening means including a threaded draft member is desirable.'

An object ofthe invention is to provide a fastening means, for use in structures built up of thin sheets of any kind and for any purpose, which includes a screw and nut couple having ordinary threads, but in which the screw, when merely tightened up in the nut, becomes securely held against accidental movement relative to the nut to an extent to permit disengagement of the threads.

A feature of the invention is the inclusion in the fastener of a means for thus holding the screw which, on the one hand, is other than an auxiliary element carried within the nut for 'acting i-n a, jamming or biting manner against the thread of the screw and characteristic of socauea nut1ocks,'and which, on the other ha'nd, does not have to rely for its action on a distortion of a sheet metal part by the screw thread.

According tothe invention, the means for hold? 'ing the screw threads against accidental separation from the nut thread engages the screw in a part thereof beyond its thread, and in a way, as predetermined, either to prevent even deliberate disengagement of the screw and nut, or to prevent accidental disengagement of these parts but to permit them to be disengaged only by the deliberate exercise of an extraordinary amount ofv effort. Also, according to the invention,- the holding means may be set to prevent such accidental loosening of the screw, from vibrations or otherwise, as would appreciably impair the desired assembly.

Another object of the invention is to provide a fastening means as above, in which the load is carried by the screw, and not by the In carrying out the invention, preferably, the holding means for the screw comprises a. spring lock, one element of which is a locking member including a cam or wedge means and carried at the inner end of the screw shank and separated from the threadedpart of the shank by an annular recess, and thev other element of which is a spring detent, of the leaf, bent wire or other suitable type, which is moved by the cam or wedge means during tightening up of 'the screw, so as automatically to seize the locking member when the screw is fully tightened. A feature of the lock thus established is an arrangement of the parts such that the detent is under tension during maintenance of the lock.

Other features and advantages rwill be hereinafter apparent.

In the accompanying drawing, illustrating various embodiments of the invention as now preferred:

Figure 1 is a sectional view, partly in elevation, showing one form of vfastening means according to the invention, and including a detent of the leaf spring type, as applied to a pair of sheet elements to secure them together.

Fig. 2 is a section taken on the line 2-2 of Fig. 1.

Fig. 3 is a view similar to Fig. 1,'showin`g another embodiment.

Fig. 4 is a section taken on the vlined-lof Fig; 3.

Fig. 5 is a view taken substantially on the line 5-5 of Fig. 6, showing still another embodiment.

Fig. 6 is a bottom plan view of the .fastening means'of Fig. 5.

Fig. `'7 is a View similar to Figi 5, and showing anI embodiment like that of Fig. 5 except for modifications in the screw and nut elements.

Fig. 8 is an enlarged fragmentary detail, showing a screw having a different type of locking member beyond its thread than that shown in the views already mentioned. i

Fig. 9 is a View similar to Fig. 8, showing a screw having still another type of locking member.

Fig. l0 is a fragmentary detail view, showing part of a nut in bottom plan, a screw in transverse section, and a detent spring of the same bent wire type as in Fig. 6, but differently shaped.

Fig. 11 is a view similar to Fig. 10, showing another of the possible variations in a detent: spring of the bent wire type.

Fig. 12 is a view similar .to Fig. 8, showing a screw Ahaving a plurality of locking members spaced along the axis of the screw.

Figs. 13 and 1,4, the former similar to Fig. 12

, tion illustrated yin the drawing includes, as will be seen, ascrew, a nut therefor, a bulbous locking member on the inner end of the screw beyond its thread, and a spring 'detent' for engaging the locking member `iwhen the screw is sent fully -home in the nut. A nut of some kind is an essential feature of the invention; the nut shown in all th illustrated forms of the invention is one individ to a particular screw, butwhenever a nut is referred to in the ,appended claims, the reference is to4 any structure including a hole having an internal thread to coact with the thread of the screw. l

In each case, the head of the screw bears against one side of the sheet structure being assembled from a plurality of sheet elements to be Joined, 'and the nut bears against the other side of such sheet structure. .'I'he parts of the sheet structure to be joined may, for instance, be the overlapped margins of wall plates, or, for another example, one or more. such plates, and a reenforcing sheet or strip for the latter. Any desired number of sheet elements, of metal or other ma-A terial, may be thus joined, but in the present case merely two thereof are shown, a sheet I5 and a sheet I8.

Referring to Figs. 1 and 2, the fastening means here shown comprises a screw Il, a nut I8, and ashell Il carrying a plurality of integral spring metal ngers 20, these for engaging a bulbous locking member.2| carried by the screw beyond its thread 22.Y 4

'Ihe locking member 2i, which here has a conical lower portion and an annularly spherical upper portion, is Joined to the inner end of the threaded shank of the screw by a reduced neck 23, thus providing an annular recess between the main body of the screw and the locking member.

Any external conformation may be given to the nut. but, conveniently, as here, it is cylindrical; as is also thelmain body of the shell I9. beyond the spring fingers 20, and which as shown houses the nut,.being sleeved tight on the same to' tener is very small,` the screw shank may have aA plain cylindrical portion between the thread and the screw head 24, accommodation for which could be provided in the nut if lengthened as shown andbored out as indicated at 2S.

For ease and speed of securement of the fastening means, by a single workman, and .also to allow the fastening means to be used vwhere the 'nut would be at a more or less inaccessible side of the sheet structure being assembled, the nut is advantageously employed'as a clincher nut, .that is, it isrestrained in some suitablemanner against turning with the sc'rew. To illustrate one s I9, V'clamped to the nut I8 as already explained, is

shown as secured,.as by rivets 26, t0 the Sheet manner of accomplishing this, the shell alcala-1 member Il; theserivets passing through extensions 21 integral with and radially offset from the main body of the shell at the end thereof opposite the spring fingers 2li. l

. In certain cases, projection' of the screw head is not objectionable.' and the head 2l of the screw I1 is shown as a half-round, one, and the plates I5 and I6 are atly overlapped and so as to bring -I into registry the apertures ltherein through which the screwl is to pass.

Withthe plates thus arranged, it is merely necessary, in order to secure the plates together, to"

insert the screw throughthe plates and into the nut until the screw thread '22 takes the thread in the nut, and then tighten up the screw, as with an ordinary screw driver. The lower conical portion of the locking member is a wedge, effective relative to allthe spring fingers 2l, and as the screw is tightened in the nut, these ilngersare spread-by the wedge. As the screw is fully sent home, the ilngers 20 snap into the recess encircling the neck 22', and become 4positioned over the locking member 2 I above its point of greatest lateral swell, as shown. I

If the ngers 20, as is recommended. are resiliently biased to less spread than that they can have when snapped into place over the locking member 2l as just described, the spring detent for the locking member provided by these fingers will be under tension, and the spring lock comprised by said member and'ngers will be one such that accidental disengagement of the screw thread from the nut'thread is positively prevented. Thengers 20 may be made more or less stimy resilient so as to preclude even temporary accidental loosening f the screw in response to intense vibrations continuing over longperiods. yYet, due to the shaping of the upper part of the locking member-2I, the fastening means may be taken down whenever desired, 'byauslng a very strong turning force on the screw Il, in a direction to loosen the same, deliberately applied at the screw head. In such case, the upper'part of the locking member 2I acts as a wedge or camming agent to spread 'the lingers 20 suiliciently to permit withdrawal of the locking member beyond these fingers.

It w111 be noted that the load a not taken by f the ngers 20 or any part of the shell Ii, but, instead. is taken wholly by the screw between the head of the latter and the nut.

Referring to Figs. 3` and 4, this shows a formv of the invention like that above described, except4 that it is the nut, marked Ila, which is secured to the sheet element ILthe shell, marked Ila,

is shortened axially and' expanded laterally, andv the screw Ila, shorter and with less turns of thread than the screw I1 of Fig. i, h a countersunk head so that the fastening sans will be flush over the sheet element I l. The conical under wall of the head 21a of the screw Ila is received in a conical depression resulting from pressing in the material of thel plates through which the shank of the screw ispassed, and the nut 18a has a recess 25a in Awhich the pressed in material of theplates is received. In this embodiment, the n ut is shownfasriveted to the plate I I, these rivets passing through extensions Ila' radially oflset from the topl of the nut, and the shell Isa is shown as crimped to the lower end of the nut. Below the nut this shell carries springilngers 2a like the Vi'lngers 20, except that the former are less sharply arched along their` 20a will be less stiiiiy resilient than the fingers 20. 'Ihe locking member 2Ia is shown as of the same shape as the member 2|, and the action of the embodiment now being described is like that of Fig. I. However, with the fingers 20a less stily resilient than the ngers 20. the amount of effort having to be applied deliberately to take down the fastening means will be less in the case of the construction of Fig. 3 than that of Fig. 1.'

'I'he shortening of the length of the screw Il a over that of the screw I1 is merely to indicate that the screw employed may have considerable variations in this regard. The showing of fewer turns of thread on the screw Ha than on the screw I1 is for the purpose of emphasizing the fact that the security of the fastening is not dependent on a large number of thread turns. Merely one full turn of thread satises all ordinary requirements, although preferably several turns will be employed. And in this connection it is remarked that the arrangement of the parts, in any form of the invention employing a fairly stiff spring, is desirably such that before thel locking member contacts its detent the screw and nut arel in threaded engagement, say to at least the extent of about one full turn of the screw thread, to facilitate final locking of the screw.

In' any case, however, it is an important feature of the invention that the locking member wedgingly or 'cammingly engages and laterally dis-` In Figs. 5 and 6, I have shown a formof the invention in which the locking member 2lb is provided with a high pitch or slope, as at 2lb', between the point of maximum'lateral'swell of the member and the threaded shankof the screw. With the locking member thus formed, the detent prevents casual rotation of the screw lin the nut, but allows the screw to be deliberately dis-4 engaged by exerting a strong turning force on the screw which, however, need not be as great as that required in'Figs. 1 and 3.

In the embodiment now being described, also, the nut I8b is shown as secured by rivets to the plate I6, and a shell` carrying the spring detent is shown ascrimped on and thereby secured to the nut, as in Fig. 3. The shell lsb is non-integral with the detent, but is a cage for enclosing and positioning thedetent, which latter is shown as in the form of a bent wire sring 29. This spring is illustrated best in Fig. 6 as shaped to provide end loops 29", and between these a pair of central and opposed arcuate bends 29 which form the detent proper. The bottom opening in the shell |912 has struck up into the same, prongs 30 which engage the loops v29 and. coact with the bottom annular wall of the shell to hold the detent 29 properly in position and against rotation with the screw.

Referring to Fig. 7, the form of the invention here shown is like that vof Fig. 5, except that the screw is illustrated as having a thread 3| of high pitch for quick application of the fastening means. In this form of the invention, the thread extends along the full length of the screw, as it may in any of the other forms shown. In the form of the invention illustrated in Fig. 7, the high pitch thread may extend over less than the-full length of the screw.

Figs. 8 and 9 show other forms -of locking members according to the invention. In Fig. 8, the locking member 2Ic on the inner end of the screw has a fiat shoulder 2Ic' just beyond its point of maximum lateral swell; while in Fig. 9 the locking member 2id has a conical formation 2Id above its point of maximum lateral swell which is transversely concavely rounded, as contradistinguished from the corresponding formations in Figs. 1 and 3, which are transversely convexly rounded. With-a construction as in Fig. 8, even deliberate disengagement of the screw from the nut 'is impossible, from the'side of the plate assembly carrying the screw head. With the construction of Fig. 9, deliberate disengagement of the screw from the nut by force exerted on the screw head is possible, but only upon the application of even more effort than would be required in connection with deliberate taking down of the construction of Fig. 1 or 3.

Referring to Figs. 10 and 11, bent Wire spring detents are illustrated differing somewhat from that of Fig. 6.

In Fig. 10, where a part of the nut is seen in bottom plan and the reduced neck 'of the screw between its threaded shank and its locking member is seen in transverse section, the spring detent is shown as in the form of a bent wire spring 32 similar to the spring 29 of Fig. 6, except that the spring 32 has a pair of central and opposed straight portions 32 constituting the detentproper. A holding and positioning shell for the spring 32, as onesimilar to the shell |91), is desirably present, although not shown.

In Fig. 11, where the nut and screw are illustrated as in Fig. 10, the spring detent is shown as -in the form of a bent wire U-spring 33 having terminal -curls 3 3' which take about pins 34 dependent from the bottom of the nut. In this case, the spring detent is direct-connected to the nut, and in a way to prevent relative rotational movement between thev detent and the nut. The pins 34 are shown as unheaded ones, and so it would be desirable here, also', to employ a suitable means for'preventing loss of the detent from the nut, such, for instance, as a shell similar to the shell |9b II'he spring detents 29, 32 and 33, like the spring detents of Figs. 1 and 3, are desirably so resiliently biased that when such detent is engaged with its locking member after full coupling of the nut and screw, the detent is under tension and applies radial as well as axial pressure on the screw.

In Fig. 12, for vthe purpose of illustrating that the screw may carry a plurality of locking membe'rs spaced along the screw axis, so that a screw of a given length may be applied in assembling sheet structures of various thicknesses, the

-screw is shown as carrying two locking members Zie and 2If.

As shown in Figs. 13 and 14, the screw may have a reduced neck portion of other than circular cross-section. The neck portion, for instance, could be so shaped as to have corner ele-` ments spaced around the same, as by making the neck portion polygonal in cross-section. As an example of one such polygonal formation, Figs.

13 and 14 illustrate a neck portion 23'v which is of square cross-section. Such a neck portion is adapted to coact with the detent which engages the locking member, in a way further to prevent rotation of the screw.

While various forms ofthe invention have been shown and described in detail, it will be understood that other variations and modifications are possible within the invention and portions of the improvements may be-usedwithout others.

I claim:

l. A fastening means for assembling .sheetstructures, comprising a nut member for placement on one side of the assembled sheets; a headed screw member for insertion through the sheets and-for engagement ofits 'thread with the thread -of the nut member to thereby hold the said assembled sheets for applying" pressure axially on the screw beyond its thread and beyond lthe nut member for'holding the screw and'nut members against relative casual rotation, ,the n said means applying the axial pressure on the screw in the direction ofthe insertion of the same through the sheets.

2. A fastening means for assembling sheet structures, comprising a nut member for placement on one side of the assembled sheets; a

" headed screw member for insertion through the sheets and for engagement of its thread with the thread of the nut member to thereby hold the sheets together; and means for holding the screw and nut members in threaded engagement against casual relative rotation, including. a locking member carried by the screw beyond its thread and adetent for the locking member secured to one side of the assembled sheets, said detent cooperating with the locking member to urge the screw member in the direction of in-l sertion4 jof the same through the sheets.

3. A fastening means as in claim 1, in which said pressure applying means includes a 'spring o for engaging the screw member beyond its thread and for maintaining such engagement while under tension toreslst casual relative rotation lbetween the screw and nut members.

4. A fastening means for overlapping margins 45 of plates, comprisinga nut memberrigidly secured to one of the plates; a headed screw member inserted and extending through aligned openings in the plates and engaging the nut member to 'thereby fasten the plates together; and means 5o )separate from'the nut member for applying radial and axial pressure onthe screw member in the direction of insertion of said screw .member to resist casual rotation thereof in the nut member.

5. A fastening means for overlapping margins 55 of plates, comprising a nut member rigidly secured to one ofthe plates; a headed screw member inserted and extending through aligned openings in the plates and engaging the nut member to thereby fasten the plates together; and means 50 separate from the nut member for applying axial pressure on the screw' member to resist casual movement thereof in the nut member and to nor-` mally u rge it in the direction of its insertion through the plate.

6. A fastening means :for assembling sheet structures, comprising a nut adapted to be p0- sitioned at one-side of the assembled sheets; -a screw for insertion through the sheets and for engagement of its threads with the threadsdof f.

sheets together; land means carried by one of l ment on o headed screw memb'er for insertion through the sheets and for engagement of its thread with the thenuttothereby hold the sheets together; means for preventing rotation of the nut, said means including a shell carried by said sheets sleeving said nut, and means formed integrally with the shell for applying pressure on the screw beyond its thread and beyond the nut member for holding the screw and nut members against relative casual -rotation. A

7. A fastening means for assembling sheet structures, comprising a nut member for placement on one side of the assembled sheets; a headed screw member for insertion through the sheets and for engagement of its thread with the thread of the nut member to thereby holdA the sheets together; and means separate from the `nut member for resistingvcasual rotation of the screw member in the nut member, said means l' including a bulbous locking member on the screw member having aA camming. surface beyond its thread, a shell carried by said nut member housing resilient detent means adapted to engage -said camming surface of the locking member to urge the screw member axially.

8. A fastening means for assembling sheet structures, comprising a nut member for placene side of, the assembled sheets.; a

thread of the nut member to thereby hold the sheets together; and means separate from the.

nut member for resisting casual rotation ofthe screw member in the nut member, said means including a bulbous locking member presenting a tapered camming surface on the -screw member beyond its thread, a shell sleeving said nut member and having an end thereof rigidly secured to the same, and a resilient detent housed and carried bysaid shell adapted to engage said camlming surface to applyan axial thrust to said yond its thread and beyond the nut member for holding the screw and nut members against relative casual rotation.

10. In a fastening means for overlapping margins of plates comprising a nut member -rigidly secured to one ofsaid plates; aheaded screw member extending through aligned openings in the plates andengaging the nut member to thereby fasten the plates together; means for re-A sisting casual rotation of thel screw member in the nut member, said meansincluding a groove formed in the screw member adjacent the end thereof, said groove having a wall tapering from the end of the screw .toward the head; and a resilient detent for engaging said tapering surface for applying a pressure thereto having'a component extending iny the axial direction of the screw. L

WALTER A. SEMION. 

